Tuning device



y 1 E. o. PETERSON Erm, 2,475,636

TUNING DEVICE Filed Sept. 20, 1946 Ihventors Eric 0. Peterson, Edward W. Forstsrom,

bywn. 49 M Them Attorney Patented july 12, 1949 I outrun Fi-iCE TUNING navrcn York Application September 20, 1946, Serial No. 698,350

Claims. (ill. 171-242) Qur invention relates to apparatus for tuning high frequency circuits and it has for its primary object to provide a new and improved tuner assembly which is simple in construction, and yet provides accurate tuning over a wide frequency band.

It is still another object of our invention to provide a new and improved tuning device which is adapted to be manufactured in large quantities from a minimum number of component parts which are easily assembled and disassembled, which is inexpensive in construction, and yet which constitutes a tuning device reliable in operation.

The novel features which we believe to be characteristic of our invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and method of operation, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawing in which Fig.1 is a perspective view, partly in section, of our improved tuning device and Fig. 2 is an exploded view of the device of Fig. 1.

Referring to Figs. 1 and 2 jointly, we have illustrated therein at I a portion of the chassis normally employed in radio and other high frequency equipment which comprises a flat metallic surface and upon which is supported a tuning device comprising a pair of insulating sup ports 2, 3, a pair of juxtaposed peripherally incomplete metallic loops 4, 5, and a movable metallic vane 6. The insulating supports 2, 3 are identical in construction and may be formed by molding a suitable insulating material, such as a phenolic resin. The supports 2, 3 are provided with an accurately located vertical slot 1 adapted to slidably receive and support the vane 6. Bosses 8 at the bottom of each of the supports are adapted to fit into two parallel slots 9 pierced or otherwise cut in the chassis I. We

provide means for accurately controlling the spacing between the loops 4, 5 which comprise two pairs of recesses III, II and l2, l3 positioned, respectively, on opposite sides of the slot 1 to receive, respectively, one of the metallic arms l4, l5 projecting outwardly from the loops 4, 5. To this end, the insulators are accurately molded so that the apertures therein are positioned with a tolerance of approximately 0.5% so that the spacing between the loops 4, 5 is held to an accuracy'ot 1%.

The loops 4, 5 may be formed by stamping a ders I6. At the lower end of each loop there is provided a terminal post l8 which is adapted to extend through apertures I9 provided in the chassis I. The terminal posts, when assembled in position on the chassis, extend through the apertures l9 so that connection may be easily made to the loops. Means are also provided for serially connecting the loops 4, 5 which comprise an eyelet 20 which is adapted tobe inserted in apertures 2| provided in an inwardly extending leg 22 of each of the loops and to be soldered thereto.

In order that the components may be held in assembled relation and also securely supported on the chassis I, we provide a U-shaped metallic spring 23 having vertical arms 24 adapted to pass through slots 25 provided in the chassis l. The arms 24 are further adapted to lie in the slots 26 provided on the outer surface of the supports 2, 3 and, at their upper ends, have inwardly directed portions 21 which are received in recesses 28 provided at the upper ends-of slots 26 and engage a shoulder 29 formed by these recesses. The portion 30 of thesprlng 23 which lies below the chassis l is formed as a z in order to provide both for lateral adjustment of the arms 24 and also to avoid the possibility of any conductive connection or contact with the terminal posts l8. Adjustment of the inductance of the device is effected by means of an operating rod 3| attached to an aperture 32 provided inthe upper part of the vane 6. In such tuning adjustment, the vane slides freely in the slots I. It wil1 be understood, of course, that in the usual radio equipment employing a device of this type, additional means are provided to hold it in adjusted position by controlling the operating rod 8|.

In assembling our tuning device, the loops 4, 5 are oriented by rotating one of the loops through with respect to the other and the arms l4, ii are inserted in the recesses Ill-l3 of the supports 2, 2, which are arranged to have their slotted surfaces in opposed relation. Such orientation of the loops 4, 8 causes alignment of the apertures It so that the eyelet Il may be inserted and soldered therein, thereby accurately spacing the loops 4, 5 for all further purposes.

The terminalposts it and thebosses 8 are positioned in the openings I! and slots 9. respectively. locating the assembly on the chassis. The arms 24 of the spring 23 are then slipped through the slots 25 with the portion It being located on the opposite side of the chassis from the assembled device. The inwardly directed portions 21 of the arms 24 are snapped into position over the shoulder 29 to pull the assembly tightly to the chassis. At-the same time, the lateral pressure provided by arms 24 compresses the supports 2, 3 laterally until they engage the shoulder ii of the metallic loops 4, I, accuratelypositioning the loops laterally.

- that we do not wish to be limited thereto since various modifications may be made, and we contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. A variable inductance comprising a pair of spaced insulators having parallel opposing surfaces and outer surfaces, each of said opposing surfaces having a slot therein and recesses on opposite sides of said slots, a pair of metallic plates having central openings and a peripheral gap, said plates having arms extending into said recesses, a metallic vane arranged for rectilinear movement in said slots, and resilient means engaging said outer surfaces to maintain said arms positioned in said recesses.

2. A variable inductance comprising a pair of spaced insulators having parallel opposing surfaces and outer surfaces, each of said opposing surfaces having a slot therein and recesses on opposite sides of said slots, a pair of metallic plates having central openings and a peripheral gap, said plates having arms extending into said recesses, a metallic vane arranged for rectilinear movement in said slots, and resilient means engaging said outer surfaces to maintain said arms positioned in said recesses, said plates having shoulders adjacent said arms for engaging said opposing surfaces.

3. A variable inductance device comprising a pair of spaced insulators having opposing faces having vertical slotstherein and a plurality of recesses on opposite sides of said slots, a pair of metallic plates having a central aperture therein and a plurality of outwardly extending arms adapted to be received in said recesses to restrain said plates against movement in a plane normal to the surfaces thereof, a metallic vane arranged for rectilinear movement in said slots, each of said insulators having a recess on the outer surface thereof, adapted to engage said outer recesses for clamping said insulators and said Plates in assembled relation, said plates having shoulders adjacent said arms engaging said opposing faces to limit the lateral movement of said insulators.

4. A variable inductance comprising a pair of parallel insulators having on their opposing faces a longitudinal slot and a plurality of recesses on opposite sides oi said slot, a pair of peripherally incomplete loop-like inductors having an inwardly directed leg and a plurality of outwardly extending arms, said inductors being so oriented that said legs are overlapping, conductive means connecting said overlapping legs, said arms being disposed in said recesses, said inductors having shoulders adjacent said arms adapted to engage said opposing surfaces. a flat metallic vane supported for longitudinal movement in said slot, said slot being of such length that said vane in its lowermost position lies above said connecting means, and resilient means engaging the outer surfaces of said insulators and said inductors in assembled relation.

5. A variable inductance for high frequency apparatus comprising a support having a plurality of parallel slots therein and a plurality of openings intermediate said slots, a pair of insulators mounted on said support and having portions extending into said slots, said insulators having opposing faces having a vertical guide therein and recesses on opposite sides of said guide, a pair of peripherally incomplete looplike inductors having outwardly extending arms adapted to be received in said recesses and an inwardly extending leg, said inductors being oriented so that said legs are overlapping, rigid conductive means connecting said overlapping legs for maintaining said inductors in parallel spaced relation, said inductors having terminals extending through said openings whereby said inductors may be connected in a desired circuit, a metallic vane movably supported in said guide, said guide terminating in a point such that the lowermost position of said vane is above said rigid connecting means, said support having a pair of apertures disposed on opposite sides of said slots,

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,137,392 Cobb Nov. 22, 1938 2,268,850 Schneider Jan. 6, 1942 2,341,346 Summerhayes Feb. 8, 1944 and resilient means- 

